Type drum printer with hammer mounted inside of and coaxial with drum



June 20, 1967 RENTARO SASAKl 3,32

TYPE DRUM PRINTER WITH HAMMER MOUNTED INSIDE OF AND COAXIAL WITH DRUM Filed om. 20, 1965 2 Sheets-Sheet" 1 INVENTOR ATTORNEYJ June 1967 RENTARO SASAKI 3,326,346

TYPE DRUM PRINTER WITH HAMMER MOUNTED INSIDE OF AND COAXIAL WITH DRUM Filed Oct. 20, 1965 2 Sheets-Sheet f:

INVENTOR Kev men JAM W ATTORNEY! United States Patent TYPE DRUM PRINTER WITH HAMMER MOUNTED INSIDE OF AND COAXIAL WITH DRUM Rentaro Sasaki, 2947-1 Ishiharacho, Takasaki Gunma Prefecture, Japan Filed Oct. 20, 1965, Ser. No. 498,658 1 Claim. (Cl. 19753) This invention relates to a typewriter of the type drum type.

In accordance with the present invention, the typewriter includes a plurality of relatively elongated type cases which are positioned at uniform angular spacings around the axis of a type drum and which extend parallel to the axis. Each type case has a pularity of types mounted therein and arranged to 'be struck and projected radially of the drum axis, biasing means being provided to bias the types to the retracted position. A guide extends longitudinally of the drum and coaxially therewithin, and this guide slidably supports a type hammer which is arranged to strike the stem or shaft rod of a selected type to project the latter.

The type hammer is arranged to perform a spacing action, to either the right or the left, and the type drum is arranged to perform not only a spacing action in coordination with the spacing action of the type hammer but also a rotary selecting action to select a particular type. The type hammer guide includes an elongated guide member on which the type hammer is slidably mounted, and a pair of hammer guides, spaced apart a fixed distance to restrain the type hammer therebetween, are slidably mounted on this elongated guide member and are displaceable by a spacing wire secured thereto to properly position the type hammer.

An object of the present invention is to provide a typewriter having movable parts lighter than those of any conventional typewriter, in which the entire type wheel moves integrally in typing and which is adapted to high speed typing.

Another object of the present invention is to provide a typewriter in which, as only the types are projected, many copies can be made and typing is clear.

A further object of the present invention is to provide a typewriter in which the pitch of types can be reduced and, with a type wheel of the same dimensions, the number of letters to be contained can be remarkable increased.

In the accompany drawings;

FIGURE 1 is a side view illustrating a typewriter embodying the present invention.

FIGURE 2 is a plan view of the same.

FIGURE 3 is an elevation of the same.

FIGURE 4 is an enlarged vertical sectional view of a part of the same.

FIGURE 5 is a perspective view of a part of the same.

Referring to the drawings, a type drum type typewriter embodying the invention includes a rotary selecting shaft 1 which, in response to a given signal, is rotated through a selected angular distance. When shaft 1 is thus rotated, it rotates a type drum 11 so that a selected type case 4 is brought into operative position with respect to the typewriter ribbon. This rotation is effected by a gear 2 rotatable with shaft 1 and meshing with a gear 3 rotatable with type drum 11. Each type case 4 has a plurality of types 7 mounted thereon, each type 7 including a shaft rod or stem 8. The types 7 are mounted on the respective type case 4 by virtue of their stems extending through aligned apertures 5 and 6 in the legs of the channel-shaped type case. Stems 8 further extend through apertures 12 into the interior of type drum 11. A type resetting spring 9 embraces each stem 8 in a type case 4 so that, after a 3 ,326346 Patented June '20, 1967 selected type is projected by a hammer 30 striking its stem 8, the type is immediately biased back to the position shown in FIG. 4.

A plurality of type cases 4 is arranged at uniform angular spacings around the supporting ring 11.

13 is a printing cam lever. When a printing cam 14 rotates with a printing shaft 15 and the tip of printing cam lever 13 drops from the lobe 16 of the cam 14, the printing cam lever 13 will rotate anticlockwise, in the direction indicated by the arrow in FIGURE 1 around a shaft 18 as a center due to the force of a spring 17. A hammer 30 fitted in a guide 19 will be pushed out and will strike with its tip the end of a stem 8 of type 7. Therefore the type 7 will be struck or projected out and a letter will be typed, through a ribbon 22, on typing paper 21 fitted on a platen 28 set opposite the type 7 as in any known typewriter. 23 is a ribbon guide.

24 is a horizontal selecting wire. The types are selected in the horizontal direction by moving the entire body, except the hammer 30 and hammer guide 25, rightward or leftward with the amount of movement varied in response to a signal, and by any known driving mechanism, Thus the position of the type is selected by the amount of movement in the direction of rotation and amount of movement in the rightward and leftward direction given to the type drum.

In typing, the typing position is displaced by a spacing wire 26 by one letter space for each typing stroke. Therefore, the typing position of the hammer 30 is determined by moving the hammer 30 by one letter space and the spacing wire 26 is moved by an amount of the movement of the hammer 30, with the addition of the movement for selecting the type with the horizontal selecting wire 24 to determine the typing position.

FIGURE 5 is a perspective view showing holding part for the hammer 30. The hammer 30 is held between the hammer guides 25, 35 which are moved with the spacing wire 26 as each letter is typed. Hammer 30 and hammer guides 25 can slide on a guide 27 but are restricted in the direction of striking movement of the hammer.

A locking lever 28 is borne on the shaft 18 and is engageable at one end with a locking rack 29 and at the other end with the gear 3 of the type drum. Locking lever 28 is operated by a cam (not illustrated) rotated by the printing shaft 15, will engage with the gear 3 and will index the type drum just before typing, so as to prevent fluctuation in typing.

In accordance with the present invention, predetermined amounts of angular and axial displacements, in predetermined directions, are initially given to the type drum. These movements are determined by signals representing letters, and, in turn, determine the type position. The spacing wire is moved once for each typing stroke to effect a predetermined spacing of the letters along the line. Hammer 30 is projected radially of the type drum, by the action of cam 16, to strike the stem of the selected type in order to make an impression on the typing paper.

What is claimed is:

A type drum type printer comprising, in combination, a type case supporting ring; a plurality of relatively elongated type cases arranged at uniform angular spacings around said supporting ring and extending parallel to the axis thereof, said type cases constituting a type drum; a plurality of types mounted in each type case for displacement radially of the type drum; respective means biasing each type to a retracted position in the associated type case; a platen positioned in operative relation to the type drum; a relatively elongated guide extending coaxially of the type drum; means mounting said guide for swinging toward said platen; a type hammer slidable longitudinally of said guide and restrained against movement laterally of said guide; said type hammer, upon swinging of said guide, striking a stem of a selected type to project the selected type toward said platen; and a pair of hammer guides slidably mounted on said elongated guide and positioned one on either side of said type hammer, said hammer guides being rigidly interconnected for conjoint movement; and means connected to said hammer guides to displace said type hammer longitudinally of said elongated guide.

References Cited UNITED STATES PATENTS 441,198 11/1890 Shuckers et a1 19753 942,825 12/1909 Hauerstein 197-53 X Hickerson 19749 Howard 19739 Griffith 197-53 Hense 19749 X Griffith 197-53 X Howard 19740 X Kleinschmidt et al. 19748 X Howard 197-49 10 ROBERT E. PULEREY, Primary Examiner.

E. S. BURR, Assistant Examiner. 

